The present invention relates to a semiconductor integrated circuit device, and more particularly to an effective technology, for instance, for a ring oscillator circuit in a PLL (phase-locked loop) circuit.
An oscillator circuit described, for instance, in Japanese Unexamined Patent Publication No. Hei 6 (1994)-188631 includes an inverting amplifier and a feedback circuit, which is coupled between the input and output of the inverting amplifier and includes, for instance, a crystal oscillator. Further, an inverter chain is additionally provided between the input and output of the inverting amplifier to avoid an oscillation start failure.